Add missing compatibility_level back

MODULE.release.bazel

diff --git a/MODULE.release.bazel b/MODULE.release.bazel
index fbcc946..fccef7b 100644
--- a/MODULE.release.bazel
+++ b/MODULE.release.bazel
@@ -1,6 +1,7 @@
 module(
     name = "rules_kotlin",
     version = "1.9.0",
+    compatibility_level = 1,
     repo_name = "rules_kotlin",
 )